It's not exactly the "paper or plastic?" debate, but chosing to go with a mechanical or tissue valve replacement is a question that patients with mitral valve failure must ponder. Until recently the popular choice has been to go with mechanical valves, since the devices provide strength and durability.
But there are drawbacks to taking the artificial route the mechanical device makes a loud ticking noise and patients often must take anticoagulation medicines to prevent clotting. And the tissue valve replacement which usually comes from pigs route can be even less promising, because it is significantly weaker and can tear easily.
However, Edwards LifeSciences (Irvine, California) is hoping to add a new dimension to the debate with its newly FDA-approved Carpentier-Edwards Perimount Magna mitral heart valve.
Wednesday's approval comes three years after the tissue based-device was given the green light in the European market and is slated to be thrust into the U.S. market, where there are nearly 40,000 mitral valve replacements a year.
"Instead of using the pig tissue, we're using bovine pericardial tissue," Donald Bobo Jr., Edwards' vice president for heart valve therapy, told Medical Device Daily. "The bovine tissue is stronger."
He said there are two main reasons why pig tissue valve replacements have become so contentious.
"The [problem] is that first, the tissue can calcify and close the valve," Bobo said. "Second, the leaflet tissue is pliable and is easier to tear. The bovine tissue is much stronger and can still calcify but it there aren't many occurrences of that happening. But we do have therapies to prevent calcification."
He added that the Carpentier-Edwards ThermaFix process is an anti-calcification technology that was developed to help mitigate tissue valve leaflet calcification, one of the primary causes of tissue valve deterioration.
The company said that the Perimount Magna valve is the first mitral tissue valve to feature an asymmetric shape that mimics the native mitral anatomy. This design advancement, which it termed "significant and unique," provides what it said is the lowest effective profile and lowest ventricular projection for any tissue mitral valve in the industry.
In addition, the replacement valve is designed specifically to optimize patient blood flow and facilitates placement above the patient's native valve opening, which may allow surgeons to implant a valve that is larger than other conventional tissue valves.
"The Perimount Magna mitral valve represents a significant advancement for patients needing mitral valve replacement. It extends the exceptional hemodynamic performance and durability of the Magna valve platform to a design that is unique and specific to the mitral valve," Bobo said. "When surgeons see the new Perimount Magna mitral valve, they immediately appreciate that its design offers an advanced and easily implantable option."
The Perimount Magna mitral valve was launched in Europe in September 2005. It incorporates features of the Carpentier-Edwards Perimount mitral valve, which the company says has demonstrated 16 years of durability.
"This valve provides patients and surgeons with an important option for mitral valve replacement," said A. Marc Gillinov, MD, staff cardiac surgeon at the Cleveland Clinic Heart and Vascular Institute, and a paid consultant to Edwards Lifesciences. "The features of the valve, including its asymmetric shape, low profile and expansive sewing cuff, are designed to provide ease of implantation in a difficult valve position, low ventricular projection and strong hemodynamic performance."
At its investor conference last December, the company said that Magna Mitral would contribute about 200 basis points to its surgical heart valve growth in 2008. It said that current 2008 surgical heart valve sales are up some 10% at about $566 million, which is toward the center point of the company's guidance of $555 million to $580 million for that business.
Analysts say the Magna Mitral could better position the company to help address new surgical valve competition from St. Jude Medical (St. Paul, Minnesota) and Sorin (Milan, Italy). Edwards cited St. Jude and its Biocor implant as a key competitor in the market. Physicians have said Biocor is an easier device to implant than previous mitral valves from Edwards, thus taking market share from the company.
Edwards bills itself as the No. 1 heart valve company in the world and the global leader in acute hemodynamic monitoring. The company's global brands, which are sold in roughly 100 countries, include Carpentier-Edwards, Cosgrove-Edwards, FloTrac, Fogarty, LifeStent, Perimount Magna and Swan-Ganz.